Aphasia is an disorder in acquired speech functions, which occurs as a result of brain damage (Non-patent reference 1). That is, it means a state in which speech functions (spoken language and written language) once acquired with growth are damaged by a brain injury due to a focus formed by a certain cause in a certain region (language area) of the cerebral hemisphere. Diseases as the cause for aphasia include brain tumor, head injury, cerebrovascular accident and the like. When the brain injury by these diseases is slight and transient, aphasia is also slight. The focus which is large or spread on the center of language area causes severe aphasia and the aphasia is more severe and recovery is difficult as the focus broadens (Non-patent reference 2).
In general, recovery of aphasia is remarkable until 3 months after the onset, gradual improvement continues thereafter, and improvement reaches plateau and symptoms are fixed 1 year after the onset (Non-patent reference 2). However, recovery of functional language is not expected in the case of severe aphasia such as total aphasia (Non-patent reference 3).
Speech therapy (language rehabilitation), which is the sole therapy for aphasia, is carried out by several kinds of methods in accordance with the symptoms of aphasia patients. As the medicinal therapy, sedatives (Sodium amytal, Meprobamate), a vasodilator (PRISCOL®) and the like have been tried from relatively old times, which are not used currently because of no reproducibility of their therapeutic effects.
In addition, a hyperbaric oxygen therapy was tried recently but no effect was found (Non-patent reference 3). From these point, there is no therapeutic method as a pharmacotherapy in Japan now, and there is no drug approved as an aphasia-treating drug.
Even in the case of the language rehabilitation as the only one method for treating aphasia, its application has limitations, and patients having critical aphasia, particularly total aphasia, and patients who already received a systematic language rehabilitation for a certain period of time and the effect reached plateau, are excluded from the subject of treatment (Non-patent reference 3). Since the situation is that no appropriate therapeutic method is available for the patients excluded from the subject of treatment, treatment and care of this disease are taken as a great social problem. Under such a situation, various agents have been investigated with the aim of finding an agent effective for this disease, but an agent which can be judged clinically useful has not been found.
On the other hand, it is known that the compound of formula (I), which is called piracetam as the generic name (trade name: MYOCALM®), shows its effectiveness against the diseases such as motion sickness, excessive movement, increase of tonus, epilepsy and the like (Patent references 1 and 2). In addition, piracetam has the following indications in Europe.
In adults:
                Symptomatic treatment of the psycho-organic syndrome whose features, improved by treatment, are memory loss, attention disorders and lack of drive.        Treatment of cortical myoclonus, alone or combination.        Treatment of vertigo and associated disorders of balance, with the exception of dizziness of vasomotor or psychic origin.        For prophylaxis and remission of sickle cell vaso-occlusive crises.In children:        Treatment of dyslexia, in combination with appropriate measures such as speech therapy.        For prophylaxis and remission of sickle cell vaso-occlusive crises.        
However, these diseases do not have any relationship with the disorders of the aforementioned aphasia. In addition, in Europe and U.S.A., therapeutic effect of piracetam is found by the combination use of speech therapy at the acute phase for the aphasia after cerebrovascular accidents. In the non-patent reference 4, investigations were carried out on the improvement of speech disorder in acute ischemia patients, in which 12 g of piracetam was intravenously administered to the patients within 12 hours and then it was administered orally at a dose of 12 g/day for 4 weeks and further at a dose of 4.8 g/day for 8 weeks. However, nothing is known about the clinical therapeutic effect of the present invention for severe aphasia in cerebrovascular accident chronic stage, which passed 3 years or more after onset of the aphasia and has no possibility of being recovered by various treatments.    Non-patent reference 1: Rinsho Shitsugosho gaku (Clinical Aphasia), Igaku Shoin, 2001, p. 2    Non-patent reference 2: Rinsho Shitsugosho gaku Handobukku (Clinical Aphasia Handbook), Igaku Shoin, 2000, p. 78, p. 74    Non-patent reference 3: Shitsugosho no Gengo Chiryo (Speech therapy of Aphasia), Igaku Shoin, 2000, p. 18, p. 48, p. 80    Non-patent reference 4: CNS Drugs, 1998, 9, Supple. 1, 41-49
Patent reference 1: JP-B-42-19093
Patent reference 2: U.S. Pat. No. 3,459,738